That's not clear at all from that text. Grammatically, faith is the closest antecedent.
Personally, it appears salvation, grace, and faith are all included.
Salvation here is deliverance, quality of life.
Faith is feminine, and the pronoun “that” is neuter, so the pronoun cannot be pointing back to faith.
Greek pronouns must agree with their antecedent in gender and number.
there is a mismatch if it refers to faith.
If you speak a gendered language you would hear the problem, but English is not gendered so it is difficult to hear that mismatch.
The word ‘gift’ is also
nominative which clarifies that it is salvation that is the gift, not faith.
There are three words that are in the subject or nominative case, and they all agree together: saved, this, and gift. The gift of God is not faith — it is SALVATION.
I could write more, but what amazes me is how this wrong understanding has permeated Christianity and has caused people to believe that God bestows the gift of faith so people can be saved, very wrong.
Paul never once wrote directly saving faith is a gift.